The Biostatistics Core will provide the data analysis support for all of the projects. The core members have participated with the project members in the design of the study, and will participate in the routine project meetings. They will either do the analysis, or provide the technical support and training to guide the analysis of the project staff. In addition, Dr. Schwartz is a co-investigator on Project 1, and will provide epidemiological as well as statistical input into that study. Dr. Schwartz is also a member of the Executive Committee of the Adminstrative Core and will participate in the general co-ordination of the Center. The members of this core will interact strongly with the data management staff in the Administrative Core, to ensure that appropriate decisions are made in data cleaning, and that the final analytical data sets are prepared in a manner to facilitate analysis.